I've been in contact with honda.uk.escalations@honda-eu.com and, so far, had two refusals to accept responsibility for the sub-standard 'material' used in side panels - when compared with earlier Jazz models and 'Crosstar' models. This was after my application for it to be repaired on (extended) warranty was refused via the dealer and a second attempt instigated by the Group Operations Director of my dealer was also rejected by Honda.
I would be very pleased, dfconnolly, if you pursued Honda by the same or any alternative route you have available!
In my claim I quoted extracts from about 15 individuals who have reported these issues on Club Jazz forum over the past 2 or 3 years (including one or two who have claimed successfully - in Italy, Japan and Boston) and the response was (paraphrased) 'whilst we acknowledge the evidence you have provided and claim of substandard materials, we are going to do nothing'.
honda.uk.escalations@honda-eu.com suggest the next step is the motor ombudsman, but I'm thinking, that before the ombudsman the 'Consumer Rights Act 2015' might be useful. It seems (I'll do more research) that for 6 years after purchase you can claim that the seller - i.e the dealer (not manufacturer - which seem unfair!) sold goods which were not of merchantable quality or durability. Durability seems the key thing here - you surely shouldn't expect car seats which have been used, in my case 45,000 miles, to fall apart - and with the same 'pattern' of falling apart as illustrated by other contributors.